com.espertech.esper.view.stat.WeightedAverageViewFactory Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of esper Show documentation
Complex event processing and event series analysis component
There is a newer version: 7.1.0
/**************************************************************************************
 * Copyright (C) 2006-2015 EsperTech Inc. All rights reserved.                        *
 * http://www.espertech.com/esper                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esper.view.stat;

import com.espertech.esper.client.EventType;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.core.service.StatementContext;
import com.espertech.esper.epl.expression.core.ExprNode;
import com.espertech.esper.epl.expression.core.ExprNodeUtility;
import com.espertech.esper.util.JavaClassHelper;
import com.espertech.esper.view.*;

import java.util.List;

/**
 * Factory for {@link WeightedAverageView} instances.
 */
public class WeightedAverageViewFactory implements ViewFactory
{
    protected final static String NAME = "Weighted-average";

    private List viewParameters;
    private int streamNumber;

    /**
     * Expression of X field.
     */
    protected ExprNode fieldNameX;
    /**
     * Expression of weight field.
     */
    protected ExprNode fieldNameWeight;

    protected StatViewAdditionalProps additionalProps;

    protected EventType eventType;

    public void setViewParameters(ViewFactoryContext viewFactoryContext, List expressionParameters) throws ViewParameterException
    {
        this.viewParameters = expressionParameters;
        this.streamNumber = viewFactoryContext.getStreamNum();
    }

    public void attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List parentViewFactories) throws ViewParameterException
    {
        ExprNode[] validated = ViewFactorySupport.validate(getViewName(), parentEventType, statementContext, viewParameters, true);

        if (validated.length < 2) {
            throw new ViewParameterException(getViewParamMessage());
        }
        if ((!JavaClassHelper.isNumeric(validated[0].getExprEvaluator().getType())) || (!JavaClassHelper.isNumeric(validated[1].getExprEvaluator().getType())))
        {
            throw new ViewParameterException(getViewParamMessage());
        }

        fieldNameX = validated[0];
        fieldNameWeight = validated[1];
        additionalProps = StatViewAdditionalProps.make(validated, 2, parentEventType);
        eventType = WeightedAverageView.createEventType(statementContext, additionalProps, streamNumber);
    }

    public View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)
    {
        return new WeightedAverageView(this, agentInstanceViewFactoryContext);
    }

    public EventType getEventType()
    {
        return eventType;
    }

    public boolean canReuse(View view)
    {
        if (!(view instanceof WeightedAverageView)) {
            return false;
        }
        if (additionalProps != null) {
            return false;
        }

        WeightedAverageView myView = (WeightedAverageView) view;
        if ((!ExprNodeUtility.deepEquals(fieldNameWeight, myView.getFieldNameWeight())) ||
            (!ExprNodeUtility.deepEquals(fieldNameX, myView.getFieldNameX())) )
        {
            return false;
        }
        return true;
    }

    public String getViewName() {
        return NAME;
    }

    private String getViewParamMessage() {
        return getViewName() + " view requires two expressions returning numeric values as parameters";
    }

    public void setFieldNameX(ExprNode fieldNameX) {
        this.fieldNameX = fieldNameX;
    }

    public void setFieldNameWeight(ExprNode fieldNameWeight) {
        this.fieldNameWeight = fieldNameWeight;
    }

    public void setAdditionalProps(StatViewAdditionalProps additionalProps) {
        this.additionalProps = additionalProps;
    }

    public StatViewAdditionalProps getAdditionalProps() {
        return additionalProps;
    }

    public void setEventType(EventType eventType) {
        this.eventType = eventType;
    }
}